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This thesis describes the study of a series of platinum complexes, with particular emphasis towards hydrosilation. Platinum bis(phosphine) azodicarbonyl complexes Pt(PRI 3)2(R20CNNCOR2) (RI = Ph, Me; R2 = Ph, Me, OEt, Pri) were synthesised and studied. Multinuclear NMR spectroscopy on Pt(PRI3)2(R20CNNCOR2) revealed that the dicarbonyl substituted azo ligand is co-ordinated asymmetrically, consistent with a five membered, Pt-N-N-C-O ring. The crystal structure of Pt(PPh3)2(Pri02CNNC02Pri) shows that the co-ordination sphere of platinum is essentially square planar and co-planar with the five-membered, Pt(1)-0(1)-C(5)-N(2)-N(1) ring. The Pt(PRI 3)lR20CNNCOR2) complexes show sensitivity towards chlorinated solvents (CH2CI2, CHCI3) under photolysis conditions forming the corresponding platinum bis(phosphine) dichloride complexes; the same products are formed in a slower thermal reaction but only for complexes with azodicarboxylate ligands. Complexes with azodicarboxylate ligands also react photochemically with ethylene in ds-THF yielding Pt(PPh3)2(C2H4) but the azodiacyl analogues are inert in this respect. Azodicarboxylate compounds R02CNNC02R (R = Et, Pri, But) are inhibitors of the catalytic activity of [(Pt {174 _(CH2=CHSiMe2hO }h {.u-( CH2=CHSiMe2)20}] for the hydrosilation reaction. The inhibited species can be decomposed thermally or photoch~mically to give active hydrosilation catalysts. It was found that the bulky azo compound But02CNNC02But was the least effective inhibitor of [(Pt{ 174 - '(CH2=CHSiMe2hO} )2(P-( CH2=CHSiMe2)20)]. The photochemistry of platinum bis(phosphine) malonates and phthalates was found to be limited, and their reactivities were much lower compared to the analogous oxalate complexes. Silyl hydride complexes, cis-Pt(PCY3)2(H)(SiR3), were synthesised from the reaction of Pt(PCY3)2 and the corresponding silane. These complexes were undergo dynamic exchange in solution. Two exchange processes were identified; the first involves mutual phosphine exchange, i.e. positional interchange between the hydride and the silyl ligands. The second process occurs at higher temperatures (above 290 K) and involves the elimination and re-addition of the silane ligand HSiR3. Thermodynamic and activation parameters are obtained for cis-Pt(PCY3)2(SiR3) (R = Ph, SiR3 = SiMe2CH2CH=CH2, SiMe2Et). The reaction of Pt(PCY3)2 with the disilane HSiMe2(l,2-C6~)SiMe2H is thought to form a Pt(IV) bis(silyl) dihydride trigonal bipyramidal species of the form, Pt(PCY3)(H)2[SiMe2(1,2-C6~)SiMe2]' where the hydride ligands are in the axial positions. All of the platinum silyl hydride complexes studied degrade thermally to form trans-Pt(PCY3)2(H)2 at, or above, room temperature.

Tesis entregada a la Universidad de Chile en cumplimiento parcial de los requisitos para optar al grado de Magíster en Ciencias Químicas. / En el presente trabajo se sintetizaron azo compuestos unidos covalentemente a fragmentos catiónicos derivados de líquidos iónicos y se estudiaron como interruptores moleculares. Se estudió en detalle el proceso de fotoisomerización trans a cis, vía fotoquímica y cis a trans vía fotoquímica y térmica de estas moléculas. Este proceso se llevó a cabo capturando la luz de un diodo emisor de luz a través de una fibra óptica, lo que resultó ser una versátil herramienta para el estudio de fotoisomerización. De este experimento se pudieron obtener las constantes de velocidad, las constantes de equilibrio, la energía libre de Gibbs, entalpía y entropía para la reacción de isomerización de trans a cis. Todos estos datos fueron obtenidos a partir principalmente del análisis de los espectros de resonancia magnética nuclear de protones por irradiación in situ, lo que constituye una nueva metodología en el estudio de fotoisomerización de azo compuestos.

Hon Wan Chee Nicole Wendy. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 85-87). / Abstracts in English and Chinese. / THESIS COMMITTEE --- p.ii / ABSTRACT (English version) --- p.iii / ABSTRACT (Chinese version) --- p.v / ACKNOWLEDGEMENTS --- p.vii / TABLE OF CONTENTS --- p.viii / LIST OF FIGURES --- p.x / LIST OF TABLES --- p.xiii / Chapter CHAPTER 1. --- General Introduction / Chapter Section 1.1 --- Introduction --- p.1 / Chapter Section 1.2 --- Electronic Structure Calculation --- p.2 / Chapter Section 1.3 --- Molecular Dynamics --- p.10 / Chapter CHAPTER 2. --- Ab Initio Molecular Dynamics Study on Thermal Dissociation of Azomethane / Chapter Section 2.1 --- Introduction / Chapter Section 2.2 --- Computational Method --- p.17 / Chapter Section 2.3 --- Results and Discussion --- p.21 / Chapter Section 2.4 --- Conclusion --- p.47 / Chapter CHAPTER 3. --- "Ab Initio Molecular Dynamics Study on Fluxionality of IF7, TeF7- and iof6-" / Chapter Section 3.1 --- Introduction --- p.49 / Chapter Section 3.2 --- Computational Method --- p.52 / Chapter Section 3.3 --- Analysis --- p.55 / Chapter Section 3.4 --- Results and Discussion --- p.56 / Chapter Section 3.5 --- Conclusion --- p.83 / REFERENCES --- p.85

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by Yung-Ho Chow. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 162-173). / ACKNOWLEDGEMENT --- p.i / ABSTRACT --- p.ii / LIST OF TABLES --- p.iii / LIST OF FIGURES --- p.iv / ABBREVIATION --- p.vi / Chapter CHAPTER 1 --- INTRODUCTION --- p.1 / Chapter 1.1 --- Azo dyes --- p.3 / Chapter 1.2 --- Chemistry of azo dyes --- p.3 / Chapter 1.2.1 --- Synthesis of azo dyes --- p.3 / Chapter 1.2.2 --- Oxidation and reduction --- p.4 / Chapter 1.2.3 --- Dyeing --- p.4 / Chapter 1.2.4 --- Staining to biological materials --- p.5 / Chapter 1.3 --- Toxicity of azo dyes --- p.5 / Chapter 1.3.1 --- Toxicity to mammals --- p.6 / Chapter 1.3.2 --- Toxicity to microorganisms --- p.6 / Chapter 1.4 --- Degradation of azo dyes --- p.9 / Chapter 1.4.1 --- Degradation of azo dyes by mammalian system --- p.9 / Chapter 1.4.2 --- Degradation of azo dyes by fungi system --- p.10 / Chapter 1.4.3 --- Degradation of azo dyes by bacteria --- p.11 / Chapter 1.4.3.1 --- Requirement of cofactors --- p.12 / Chapter 1.4.3.2 --- Effect of oxygen --- p.13 / Chapter 1.4.3.3 --- Effect of cell permeability --- p.14 / Chapter 1.4.3.4 --- Redox potential and rate of dye degradation --- p.15 / Chapter 1.4.3.5 --- Rate of dye degradation --- p.15 / Chapter 1.4.4 --- Azo-reductase --- p.18 / Chapter 1.4.4.1 --- Microsomal azo-reductase --- p.18 / Chapter 1.4.4.2 --- Bacterial azo-reductase --- p.19 / Chapter 1.5 --- Immobilization of microorganisms --- p.19 / Chapter 1.5.1 --- Gel matrix for entrapment --- p.20 / Chapter 1.5.2 --- Effect of gel entrapment to microbial cells --- p.21 / Chapter 1.5.2.1 --- Reduced diffusion of substrates in gel --- p.22 / Chapter 1.5.2.2 --- Effects in growth patterns --- p.22 / Chapter 1.5.2.3 --- Protection of entrapped microbial cells --- p.23 / Chapter 1.5.2.4 --- Increase metabolic activities --- p.26 / Chapter 1.5.2.5 --- Reduction of water activity --- p.27 / Chapter 1.5.2.6 --- Prolongation of products formation --- p.27 / Chapter 1.6 --- Application of immobilized microorganisms in bio-remediation of azo dyes --- p.28 / Chapter 1.7 --- Purpose of study --- p.28 / Chapter CHAPTER 2 --- MATERIALS AND METHODS --- p.29 / Chapter 2.1 --- Materials --- p.31 / Chapter 2.1.1 --- Chemicals --- p.31 / Chapter 2.1.2 --- Bacteria --- p.36 / Chapter 2.1.3 --- Instruments --- p.36 / Chapter 2.1.4 --- Media --- p.37 / Chapter 2.1.4.1 --- Luria Broth medium --- p.37 / Chapter 2.1.4.2 --- Minimal medium --- p.37 / Chapter 2.2 --- Methods --- p.38 / Chapter 2.2.1 --- Culture of Pseudomonas sp. ADD16-2 --- p.38 / Chapter 2.2.2 --- Purification and characterization of azo-reductase --- p.38 / Chapter 2.2.2.1 --- Preparation of crude extract --- p.38 / Chapter 2.2.2.2 --- Purification of azo-reductase --- p.39 / Chapter 2.2.2.2a --- Preparation of SDS-polyacrylamide gel --- p.40 / Chapter 2.2.2.2b --- Sample preparation and application --- p.41 / Chapter 2.2.2.2c --- Electrophoresis condition --- p.41 / Chapter 2.2.2.2d --- Staining of gel by Commasie blue --- p.41 / Chapter 2.2.2.3 --- Measurement of azo-reductase activity --- p.41 / Chapter 2.2.2.4 --- Determination of effect of pH to azo- reductase activity --- p.42 / Chapter 2.2.3 --- Measurement of azo dye decolourization rate by whole cells of Pseudomonas sp. ADD16-2 --- p.42 / Chapter 2.2.3.1 --- Preparation of cells --- p.42 / Chapter 2.2.3.2 --- Measurement of azo dye decolourization rate --- p.43 / Chapter 2.2.4 --- Measurement of azo dye decolourization rate by crude extract of Pseudomonas sp. ADD16-2 --- p.43 / Chapter 2.2.5 --- Determination of dye degradation products by High Performance Liquid Chromatography (HPLC) --- p.46 / Chapter 2.2.6 --- Measurement of redox potential of azo dyes --- p.47 / Chapter 2.2.7 --- Determination of the effect of cell permeation agents on dye degradation --- p.48 / Chapter 2.2.8 --- Determination of cell permeability --- p.48 / Chapter 2.2.9 --- To study the effect of the presence of dye degradation products or added aromatic amines to dye degradation --- p.49 / Chapter 2.2.9.1 --- Whole cell reactions --- p.50 / Chapter 2.2.9.2 --- Crude extract or purified azo-reductase reaction --- p.50 / Chapter 2.2.10 --- Immobilization of cells by different matrix --- p.50 / Chapter 2.2.10.1 --- Preparation of cells for immobilization --- p.50 / Chapter 2.2.10.2 --- Immobilization by calcium alginate --- p.51 / Chapter 2.2.10.3 --- Immobilization by K-carrageenan --- p.51 / Chapter 2.2.10.4 --- Immobilization by polyacrylamide gel --- p.52 / Chapter 2.2.10.5 --- Immobilization by agarose gel --- p.52 / Chapter 2.2.10.6 --- Measurement of viability of immobilized cells --- p.53 / Chapter 2.2.10.7 --- Measurement of azo dye degradation rate in immobilized cell system --- p.53 / Chapter 2.2.10.8 --- Measurement of intracellular K in calcium alginate immobilized cells --- p.53 / Chapter 2.2.10.9 --- Long term batch culture of immobilized cells --- p.53 / Chapter 2.2.11 --- Determination of toxicities of azo dyes and aromatic amines --- p.54 / Chapter CHAPTER 3 --- RESULTS --- p.55 / Chapter 3.1 --- Purification of azo-reductase 、 --- p.56 / Chapter 3.2 --- Properties of azo-reductase --- p.63 / Chapter 3.3 --- Degradation of azo dyes --- p.73 / Chapter 3.3.1 --- Degradation profiles --- p.73 / Chapter 3.3.2 --- Products of dye degradation --- p.80 / Chapter 3.3.3 --- Effect of cell permeability on dye degradation rate --- p.94 / Chapter 3.3.4 --- Induction of dye degradation rate by prior dye degradation exercise or by direct addition of aromatic amines --- p.97 / Chapter 3.4 --- Effect of immobilization --- p.114 / Chapter 3.4.1 --- Effect of different immobilization matrix --- p.114 / Chapter 3.4.2 --- Toxicities of different azo dyes and aromatic amines to free and immobilized cells --- p.124 / Chapter 3.4.3 --- Effect of azo dyes and aromatic amines at high concentrations on free and on immobilized cells --- p.124 / Chapter CHAPTER 4 --- DISCUSSION --- p.145 / Chapter 4.1 --- Degradation of azo dyes by Pseudomonas sp. ADD16-2 --- p.146 / Chapter 4.2 --- Permeability of azo dyes in Pseudomonas sp. ADD 16-2 --- p.150 / Chapter 4.3 --- Induction of dye degradation rate --- p.155 / Chapter 4.4 --- Effect of immobilization --- p.159 / CONCLUSION --- p.161 / REFERENCE --- p.162 / APPENDIX --- p.174 / appendix 1 Structures of azo dyes that have similar structures to Orange G --- p.175 / appendix 2 Absorption profiles of azo dye degradation products taken at different time intervals --- p.178 / appendix 3 Effect of pre-incubation time to dye degradation rate of Orange I by Pseudomonas sp. ADD16-2 --- p.183 / appendix 4 Effect of calcium ions (0-0.2 M) to (A) dye degradation and (B) viability of cells --- p.185 / appendix 5 Effect of ATP on induction effect of Orange I on whole cells of Pseudomonas sp. ADD16-2 --- p.187 / appendix 6 Summary of azo dyes that were degraded by Pseudomonas putida AD1 cells --- p.189

The laser-induced holographic gratings in the azo-dye-doped liquid crystals have been investigated by changing the temperature, and the concentration of the sample, the intensity of the two writing beams, and the polarization of probe beams. The cw Nd:YAG laser has been employed as the writing beams and the cw He-Ne laser has been employed as a real-time probe beam to detect the first order diffraction singals. The gratings are the results of photo-isomerization of azo dye and the structure alignment of liquid crystals. The model has been established to explain the first order diffraction signals, the mechanism of gratings formation and the temperature dependence.

Transparent conductive aluminum-doped zinc oxide(AZO) thin films were synthesized by reactive RF magnetron co-sputtering system with metallic zinc and aluminum targets under oxygen atmosphere. Systematic study on the fixed sputtering power of the Zinc target (PZn) and the variation of the sputtering power of the Aluminum target (PAl) on structural, electrical and optical properties of AZO thin film was mainly investigated in this work. We found that the microstructure of AZO films would be obviously transformed from rice-like crystalline structure to nanocrystalline (nano-column) structure with the increasing of the sputtering power of the Aluminum target (PAl) . Nanocrystalline AZO films were formed at the specific sputtering power ratio of metallic targets (PAl/ PZn=1) . X-ray diffraction (XRD) spectra revealed that nanocrystalline AZO films highly preferred c-axis orientation (002) was growth in perpendicular to the substrate. The optical refractive index (n) of nanocrystalline AZO films had significantly lower values than others of microstructure AZO films, and this suggested the low optical dispersion in nano-column structure . Furthermore, the electronic properties of AZO films with the proper sputtering power of the Aluminum target (PAl) evidently improved under rapid temperature annealing (RTA) process. It suggested that both high annealing temperature(400¢J) and rapid cooling time(15min) are main factors to decrease the sheet resistances due to the maintenance of high temperature structural phase. The results of X-ray photoelectron spectroscopy (XPS) show that RTA process can decrease oxidized Al in order to decrease the sheet resistances.

In this study, the AZO thin films were deposited with various manufacturing conditions, such as working pressure of oxygen and substrate temperature, by e-beam evaporation. The microstructure of the AZO film was observed by SEM and AFM. Sheet resistance was measured using four-point probe method. Optical transmittance was measured in the visible range by UV spectrophotometer. Finally, AZO transparent film was used as a substitute for ITO to fabricate the radiation-resistant glasses. The optimum parameters for depositing AZO films are glass substrates of 80¢J and working pressure of 1¡Ñ10-4 Torr. The film resistance is 9.2¡Ñ10-4 £[-cm with a film thickness of 60 nm. The refractive index was measured to be 2.05 at a wavelength of 510 nm. The optical transmittance of the prepared films was above 83 % in the visible range. The manufacturing conditions for depositing AZO multilayer coatings are working pressure of 5.0¡Ñ10-5 Torr, ion gun working pressure of 6.0¡Ñ10-5 Torr, voltage of 6.2 V, oxygen gas flow rate of 36 sccm and glass substrates of 80¢J. The optical transmittance of the glass was above 94 % in the visible range.

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